I recently bought an XPG SX8200 Pro M.2 PCIe for my X58 ( Asus P6T Deluxe v2 ).
I bought an ICY Box PCIe extension card for it.
Downloaded DUET, installed on a USB stick. Transfered the partition from the usb stick to an older OCZ SATA II SSD.
I am now booting from the SSD which then boots from the PCIe.
It works quite well. I recommend it. I am still quite happy with my X58 system! Just need a new gfx card soon.
However I am not completely satisfied with the benchmarks seeing that other people can achieve >3k speeds.
GFX card is in slot 1, NVMe in slot 2.
Any tips?